The present invention relates to a method of separating potassium fluoride from potassium salts of organic acids in aqueous mixtures containing both. The salts can be independently recovered after separation.
Chemical processes involving fluorinated compounds as reactants or products often result in an aqueous product or by-product stream containing essentially, but not necessarily exclusively, potassium fluoride and one or more potassium salts of organic acids. The high value of potassium fluoride as compared with sodium fluoride both as a reactant and as a sales item makes it attractive to develop processes resulting in such mixtures. Examples of processes of this type include processes in which a fluorinated hydrocarbon or heterocyclic compound, such as a fluoropyridine, is made to react with potassium hydroxide to form potassium fluoride and a potassium salt of an hydroxylated compound and processes wherein hydrogen fluoride is employed or formed as a by-product in the presence of an organic acid and is neutralized with aqueous potassium hydroxide. In processes of this type, however, it is important from cost and waste disposal points of view to recover both the potassium fluoride and the potassium salts of organic acids that are present. The potassium fluoride is ideally recovered in a form that will allow for its recycle, alternate use, or sale. The potassium salts of organic acids are ideally recovered in a form suitable for further chemical processing, alternate use, or sale. The development of a process that achieves these ideals would be of considerable commercial value.